含四嗪单元的聚对苯撑乙炔类聚合物的合成及性能

通过Sonogashira偶联反应,以二(三苯基膦)二氯化钯作为催化剂,将3,6-二氯-1,2,4,5-四嗪分别与1,4-二乙炔基-2,5-二辛氧基苯和1,4-二乙炔基-2,5-二(十二烷氧基)苯交替共聚合成了主链中含四嗪单元的新型聚对苯撑乙炔类π-共轭聚合物P1、P2。经傅里叶变换红外光谱、核磁共振氢谱、紫外-可见光谱、荧光光谱、循环伏安、X射线粉末衍射、热重分析等测试手段对共聚物P1、P2进行了表征。结果表明,所得聚合物P1和P2对常用有机溶剂的溶解性不好。与P2相比,P1有一定的结晶性。P1、P2的紫外-可见最大吸收波长均在450nm处出现。P1与P2在CHCl3溶液中的最大发射峰出现在480nm处。与2-十二烷基-1,2,3-苯并三氮唑聚对苯撑乙炔类聚合物相比,P1、P2具有较高的相对荧光量子效率。循环伏安测试显示聚合物P1、P2均在0~2.0V出现明显的p-掺杂峰。     

含有不同烷氧基侧链的聚对苯乙炔(PPV)衍生物的合成与性能表征

采用强碱去卤缩合法合成了聚(2-甲氧基-5-丁氧基)对苯乙炔(PMOBOPV),聚(2-甲氧基-5-辛氧基)对苯乙炔(PMOCOPV),(2-甲氧基-5-异辛氧基)对苯乙炔(iso-PMOCOPV)和聚(2-甲氧基-5-十二烷氧基)对苯乙炔(PMODOPV)四种含有不同烷氧基侧链的聚对苯乙炔(PPV)的衍生物。利用傅里叶变换红外光谱、核磁共振谱、热失重曲线、紫外-可见光吸收光谱和光致发光光谱对聚合物的结构和性能进行了表征。并通过实验确定了适宜的合成反应条件,例如催化剂和原料配比、叔丁醇钾的用量等。结果表明合成的聚合物具有良好的热稳定性和溶解性,聚合物的紫外吸收波长最大在492nm,荧光光谱的最大发射波长在555nm左右。     

烷氧基对聚对苯撑发光性能的影响EI

:采用 Scholl反应 ,以硝基苯作溶剂 ,无水三氯化铁为催化剂 ,合成了系列可溶性烷氧基对称二取代的聚对苯撑 (DAO- PPP) ,并用多种手段对其结构进行了表征 ,研究了聚合物的光致发光性能。实验表明 ,烷氧基的引入不但明显改善了 PPP的溶解加工性能 ,而且随烷氧基侧链链长的改变 ,聚合物的最大紫外吸收峰、带隙 Eg、光致发光(PL)最大发射峰及其发射强度都呈现规律性的变化 。     

纳米级聚噻吩衍生物的固相聚合

首次采用固相聚合法在室温条件下制备了聚(3,6-二噻基-哒嗪)[P(DThPD)],聚(1,4-二噻基-苯)[P(DThPh)]和聚(4,7-二噻基-2,1,3-苯并噻二唑)[P(DThB)].并用红外光谱、紫外-可见光光谱、荧光光谱、电子扫描显微镜、电子透射显微镜、循环伏安(cyclic voltammogram)等测试方法,对聚合物进行表征.结果表明,固相聚合法合成的P(DThPD)和P(DThPh)具有纳米颗粒串连的棒状或环状结构;P(DThPD)分别在336 nm、450nm和580nm(w)处有吸收峰;P(DThPh)分别在325nm和410nm处有吸收峰;P(DThB)分别在460nm、550nm和700nm处有吸收峰.P(DThPh)和P(DThB)分别在488nm和599nm处有较强的荧光.循环伏安测试表明,固相聚合法合成的3种聚合物均具有较好的电化学活性.     

含二噻基哒嗪的聚芳炔类衍生物的合成与性能研究

以四(三苯基磷)钯(Pd(PPh3)4)和CuI作为催化剂,在二异丙胺和四氢呋喃溶液中,采用宽能带的1,4-二乙炔基-2,5-二(十二烷氧基)苯(PE)和窄能带的3,6-双(5′-溴-2′-噻吩)-哒嗪(TPD)以不同配料比合成了一系列新型聚芳炔。长链烷氧基的存在使得此类聚合物在常用的有机溶剂中具有较好的溶解性和成膜性。通过对上述聚合物的紫外-可见吸收、荧光发射及循环伏安等基本性能进行探讨可知,共聚物在THF溶液中的荧光量子效率为51%～61%;随着共聚物中TPD含量的增加,共聚物薄膜的吸收起始波长及荧光发射波长均有红移。聚合物薄膜的最大发射峰位于540～551nm。     

含2-异丙基氨基-4,6-二(3,4-乙撑二氧噻基)-1,3,5-三嗪π-共轭聚合物的合成及性能

以二价钯配合物作为催化剂,将2-异丙基氨基-4,6-二(2′-溴-3,4-乙撑二氧噻基)-1,3,5-三嗪分别与1,4-二乙炔基-2,5-二辛氧基苯、1,4-二乙炔基-2,5-二(十二烷氧基)苯、2,7-二(4,4,5,5-四甲基硼烷基)-9,9-二辛基芴交替共聚合成了3种π-共轭聚合物P1,P2和P3。经傅里叶变换红外光谱、氢核磁共振谱、紫外-可见光谱、荧光光谱、循环伏安法、X射线粉末衍射和凝胶渗透色谱等测试手段对其进行了表征,并对聚合物在CHCl3溶液的酸致变色行为进行了研究。结果表明,得到的聚合物在CHCl3中的紫外-可见最大吸收波长分别在443nm和431nm处出现。在CHCl3溶液中聚合物P1,P2和P3最大发射峰分别位于507nm,511nm和543nm,其聚合物薄膜的最大发射波长分别为573nm,557nm和559nm。与P1和P2相比,P3的酸致变色敏感性高于2个数量级。聚合物P1和P2均在-2.0~0V出现n-掺杂峰。聚合物X射线衍射谱图显示聚合物均有一定的结晶性。     

可溶性聚吡咯甲烯的超声辐射合成

首先利用超声辐射法制备聚{(3-丁酰基)吡咯-[2,5-二(对十四烷氧基苯甲烷)]}(PBPDTBA),然后将PBPDTBA醌化制备聚{(3-丁酰基)吡咯-[2,5-二(对十四烷氧基苯甲烯)]}(PBPDTBE),采用红外光谱、紫外可见吸收光谱、热失重曲线和荧光光谱等对产物的结构和性能进行表征与分析。结果表明,PBPDTBE易溶于多种有机溶剂,在氯仿中的溶解度为0.66 g/mL;PBPDTBE氯仿溶液和薄膜在400 nm～600 nm具有显著的光学吸收,共轭吸收峰分别位于455nm和462nm;PBPDTBA和PBPDTBE的热分解过程分为两个阶段,分别对应丁酰基和对十四烷氧基苯基的分解,初始分解温度分别为210.45℃和230.01℃。PBPDTBA和PBPDTBE均为绿色发光材料,最大发射波长分别为514nm和520nm。     

聚3-烷基噻吩系列物的合成与表征

采用Fe(III)催化剂合成法合成聚3-丁基噻吩(P3BT)、聚3-己基噻吩(P3HT)和聚3-十二烷基噻吩(P3DDT)。用GPC和1 H-NMR对所合成的聚合物的相对分子质量和结构进行表征,用SEM对所合成的聚合物的表面形貌进行观察,并用紫外-可见吸收光谱和荧光光谱研究3种聚合物氯仿溶液的光学性能。结果表明,用该方法合成的聚合物以非晶态形式存在;具有较高的相对分子质量;在氯仿溶液中,P3BT、P3HT、P3DDT的最大吸收峰分别为:436nm、437nm和430nm,最大发射峰分别为570.0nm、581.2nm和573.8nm。综合分析发现P3HT更适于用做聚合物太阳能电池材料。     

含2,3-二(5′-辛基噻吩基)喹喔啉单元荧光聚合物的合成及性能EI北大核心CSCD

以二价钯配合物作为催化剂,通过Sonogashira或Suzuki碳碳偶联反应制备了3种含2,3-二(5′-辛基噻吩基)喹喔啉单元的聚苯撑乙炔类(P1)、聚芴类(P2)和聚咔唑类(P3)π-共轭荧光聚合物。经傅里叶变换红外光谱、核磁共振氢谱和X射线粉末衍射对其结构进行了表征。利用紫外-可见光谱、荧光光谱和循环伏安等测试手段对其光学与电化学性能进行了研究,并研究了聚合物在CHCl3-CF3COOH溶液中的酸致变色行为。结果表明,3种聚合物在氯仿溶液和薄膜状态下的长波长处的紫外-可见最大吸收峰分别出现在449nm、420nm、418nm和538nm、425nm和420nm处。3种聚合物在氯仿溶液和薄膜状态下的荧光发射峰分别出现在556nm、529nm、558nm和599nm、556nm、569nm处,其在薄膜状态下分别发深红色、亮黄色和橙红色荧光。聚合物的相对荧光量子效率分别为18.1%、26.6%和16.8%。与P1和P3相比,P2显示较好的酸致变色行为,并在三氟乙酸浓度范围为2.692×10^(-3)~40.38×10^(-3) mol/L之间表现出酸浓度与吸光度之间优良的线性关系。通过循环伏安测试,聚合物均具有一定的空穴传输行为。     

含2,3-二(5′-辛基噻吩基)喹喔啉单元荧光聚合物的合成及性能

以二价钯配合物作为催化剂,通过Sonogashira或Suzuki碳碳偶联反应制备了3种含2,3-二(5′-辛基噻吩基)喹喔啉单元的聚苯撑乙炔类(P1)、聚芴类(P2)和聚咔唑类(P3)π-共轭荧光聚合物。经傅里叶变换红外光谱、核磁共振氢谱和X射线粉末衍射对其结构进行了表征。利用紫外-可见光谱、荧光光谱和循环伏安等测试手段对其光学与电化学性能进行了研究,并研究了聚合物在CHCl3-CF3COOH溶液中的酸致变色行为。结果表明,3种聚合物在氯仿溶液和薄膜状态下的长波长处的紫外-可见最大吸收峰分别出现在449nm、420nm、418nm和538nm、425nm和420nm处。3种聚合物在氯仿溶液和薄膜状态下的荧光发射峰分别出现在556nm、529nm、558nm和599nm、556nm、569nm处,其在薄膜状态下分别发深红色、亮黄色和橙红色荧光。聚合物的相对荧光量子效率分别为18.1%、26.6%和16.8%。与P1和P3相比,P2显示较好的酸致变色行为,并在三氟乙酸浓度范围为2.692×10~(-3)~40.38×10~(-3) mol/L之间表现出酸浓度与吸光度之间优良的线性关系。通过循环伏安测试,聚合物均具有一定的空穴传输行为。     

Hopping and optical absorption of electrons in nano-porous crystal 12CaO·7Al2O3

Recently it has been discovered that a nano-porous main group oxide 12CaO·7Al₂O₃ (C12A7) can be converted from a wide-gap insulator to a good transparent conductor. Using ab initio modelling we explain good conductivity of this material by very small barriers for hopping of localised electrons between neighbouring positive cages. We show that optical absorption of C12A7 in infrared region and at energies higher than 2.7 eV is due to inter-cage and intra-cage electron transitions, respectively. The proposed mechanisms can be useful in further search for conducting transparent media.     

Bicycle-related injuries among young children related to age at debut of cycling

This study focuses on bicycle-related injuries among young children and the effect of being an inexperienced beginner related to age at debut of cycling. The study was based on a random stratified population sample of 1200 children aged 4-15 years in Bergen, Norway. Data about age at debut of cycling, cycling habits and any previous bicycle-related injuries were collected. A child was defined as a beginner within the first 12 months of active cycling. Relation between the first bicycle-related injury and age at debut was analysed by the Kaplan-Meier method. The risk of getting injured during the first 12 months of active cycling were significant lower for children aged 7 or 8 years at the debut of cycling compared to younger children (hazard ratio = 0.78, P < 0.001). Children cycling more than 1h per week were at greater risk of getting injured during the first 12 months than those who cycled less (hazard ratio = 1.95, P = 0.014). This study shows that the risk of getting injured during the first 12 months of active cycling is reduced if bicycling debut is delayed until 7 or 8 years instead of at 4 or 5 years.     

White luminescence of Dy3+ ions doped 12CaO 7Al2O3 nanopowders under UV light excitation

12CaO 7Al2O3:Dy3+ nanopowders were successfully synthesized by the chemical co-precipitation method. X-ray diffraction result shows that the single 12CaO 7Al2O3 phase is formed with Dy3+ ions to replace the Ca2+ ions in the host of 12CaO 7Al2O3. The yellow and blue emissions, attributed to the forced electric dipole transition of 4F(9/2) --> 6H(13/2) centered at 571 nm and the magnetic dipole transition of 4F(9/2) --> 6H(15/2) centered at 480 nm, respectively, were observed. The integrated intensity ratios of yellow to blue increase from 1.63 to 1.70 with Dy3+ concentration increasing from 0.8 to 2.0% for the as-prepared 12CaO 7Al2O3:xDy3+ phosphor. The significantly enhanced emission intensities of 12CaO 7Al2O3:1.0% Dy3+ phosphor annealed at 900 degrees C for 2 hours in vacuum ambient could be ascribed to the decrease of OH(-) groups and the change of the surface topography. The thermal stability and the Commission International de l'Eclairage coordinates were also investigated. All the photoluminescence characteristics indicate that Dy3+ ions doped 12CaO 7Al2O3 may be a good candidate for the solid state lighting phosphor as well as white light-emitting diodes.     

羟基丁酸与羟基辛酸共聚体骨组织工程支架的初步研究

采用粒子滤出/冷冻干燥复合法制备羟基丁酸与羟基辛酸共聚体[P(HB-HO)]多孔支架,并进行扫描电镜观察、孔隙率和力学性能检测以及体外降解和细胞相容性实验.结果表明,P(HB-HO)多孔支架孔隙分布均匀,连通性好,孔隙率为50%～90%时,抗压强度在1.7～6.2MPa之间,十二周体外降解率约为20%;与P(HB-H0)复合培养的小鼠成骨样细胞MC3T3-E1黏附率高,生长状态良好.证明P(HB-HO)具有良好的理化性能和细胞相容性,有望成为一种具有临床应用价值的骨组织工程支架材料.     

Ni12P5微球的溶剂热合成与表征

以硫酸镍(NiSO4.7H2O)作为镍源,以乙二醇和水作为混合溶剂,利用溶剂热法成功地制备了磷化镍(Ni12P5)微球。X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)和高分辨透射电镜(HRTEM)等分别对所制备样品进行了表征。结果表明,所得产物为纯的四方相磷化镍(Ni12P5)微球,粒径约为2～5μm;研究了不同实验参数对样品尺寸、形貌及微球形成过程等的影响。最后对磷化镍微球的发光性进行了研究。     

嵌段共聚有机硅氧烷的合成及其氧化热稳定性研究

采用对－双（二甲基－锂氧硅基）苯撑作引发剂，Ｎ，Ｎ－二甲基甲酰胺作促进剂，不同的有机环四硅氧烷作单体，制备了数种不同组成的聚二苯基硅氧烷（Ｐ）－聚二甲基－甲基乙烯基硅氧烷（ＭＶ）－聚二苯基硅氧烷（Ｐ）三嵌段（Ｐ－ＭＶ－Ｐ）共聚物。这些嵌段共聚物，经石油醚溶解，乙醇萃取低分子量物质，得到了具有良好的氧化热稳定性的有机硅材料。     

Phase Relations in the Systems M–Mn–P (M = Cr, Mo, W, Re)

The 1070-K phase relations in the M–Mn–P (M = Cr, Mo, W; 67 at. % P) and Re–Mn–P (50 at. % P) systems were studied by x-ray diffraction. The existence of the known phosphides Mo₄Mn₆P₅ and (Mn,W)₁₂P₇ was confirmed, and a new phase with the general formula (Mn,Mo)₁₂P₇ and stoichiometry range Mo_4.6–1.8Mn_7.4–10.2P₇ was identified. Its structure was determined by powder diffraction profile analysis (R = 0.074): Cr₁₂P₇ structure type, sp. gr. P6, a = 0.94929(8) nm and c = 0.33565(3) nm for Mn_7.4Mo_4.6P₇. The Mo and Mn atoms in the structure of this phase were shown to occupy all positions at random. In addition to the known solid solutions (Cr,Mn)₃P (Ni₃P structure type), (Cr,Mn)₁₂P₇ (Cr₁₂P₇), (Cr,Mn)P, and (Mn,Mo)P (MnP), we revealed new solid-solution series: (Cr,Mn)₂P (Cr₂P), (Mn,Cr)₂P (Fe₂P), (Mn,Mo)₃P (Ti₃P), (Mo,Mn)₃P (-V₃S), (Mo,Mn)P (WC), (W,Mn)P (MnP), (Mo,Mn)P₂, and (W,Mn)P₂ (MoP₂). The Re–Mn–P system was found to contain neither ternary phosphides nor solid solutions.     

Creep behaviour of P91/GTR-2CM/12Cr1MoV dissimilar joint predicted by the modified Theta method

Creep behaviour of P91, 12Cr1MoV steels and the P91/12Cr1MoV dissimilar joint were investigated at 823 K. Results show that the creep strength of P91 is much higher than 12Cr1MoV and than the dissimilar joint. The stress dependence of minimum creep rate and rupture life for both steels and the dissimilar joint obeyed Norton’s power law. The values of stress exponent are similar for 12Cr1MoV steel and the dissimilar joint in high stress region, indicating similar creep mechanism. However, the creep behaviour at 140 MPa for the dissimilar joint showed deviation from the other higher stresses, indicating different creep mechanism as the stress is decreasing. Microstructure showed that creep ruptured on the 12Cr1MoV side of the dissimilar joint as conducted in the high stress region, whereas ruptured on the carbon decarburized zone as conducted in the low stress region. Fracture location changed from 12Cr1MoV base metal to inter-critical heat affected zone as the creep time going. A modified theta equation was proposed to predict the creep behaviour, and the random errors from fitting to experimental creep data were smaller than obtained from the traditional theta method. The predicted creep behaviour showed good agreement with experimental ones.     

Synthesis and electrochemical probing of water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes

Water-soluble poly(sodium 4-styrenesulfonate-co-acrylic acid)-grafted multiwalled carbon nanotubes (MWNT-g-P(SSS-co-AA)) with core-shell nanostructure were successfully synthesized by in situ free radical copolymerization of sodium 4-strenesulfonate (SSS) and acrylic acid (AA) in the presence of MWNTs terminated with vinyl groups; their structure was characterized by FTIR, (1)H NMR, Raman, TGA and TEM. The results showed that the thickness and content of the copolymer layer grafted onto the MWNT surface are about 7-12?nm and 82.3%, respectively. The P(SSS-co-AA) covalently grafted on MWNTs provides MWNT-g-P(SSS-co-AA) with good hydrophilicity and solubility in water. Then a novel MWNT-g-P(SSS-co-AA)-modified glassy carbon electrode was fabricated by coating; its electrochemical properties were evaluated by electrochemical probe of K(3)[Fe(CN)(6)], and its catalytic behaviors to the electrochemical oxidation processes of dopamine (DA) and serotonin (5-HT) were investigated. Since the MWNT-g-P(SSS-co-AA)-modified electrode possesses strong electron transfer capability, high electrochemical activity and catalytic ability, it can be used in sensitive, selective, rapid and simultaneous monitoring of biomolecules.     

Characterization and luminescence of Eu3+ ions doped 12CaO 7Al2O3 nanopowders

Eu3+ ions doped 12CaO 7Al2O3 (C12A7) powders with different Eu3+ concentrations were prepared by sol-gel combined with solid state reaction method. The results of XRD and Raman spectra showed that single cubic phase polycrystalline C12A7:Eu3+ powders were prepared. The absorption peaks attributed to f-f transition of Eu3+ ion can be observed, indicating that Eu3+ had been incorporated into C12A7 lattice site. Visible PL peaks around 578, 588, 614 nm were ascribed to 5D0 --> 7FJ (J = 0, 1, 2) transitions of Eu3+ under the excitation of 488 nm line. The PL of C12A7:Eu3+ showed the strongest emission intensity at Eu3+ concentration of 0.5 at%. Two different types of Eu3+ centers were identified by the two lines from 5D0 --> 7F0 transition emission. The doping mechanism of C12A7:Eu3+ might be attributed to Eu3+ ions substitution for two types of Ca2+ lattice sites in C12A7. The temperature dependent PL spectra of Eu-doped C12A7 were measured in the range from 100 to 300 K under the excitation of 488 nm laser line. The PL intensities as a function of temperature were well fitted by using a unified theoretical model, considering thermal activation and nonradiative energy transfer processes.